The research program compares memory for thought with memory for perceptions. Of specific interest are the "reality monitoring" processes people use to decide whether information initially had an internal or external source. The research program is guided by a model of reality monitoring (Johnson & Raye, 1981) that proposes that decision processes take advantage of, among other things, average differences in the characteristics of traces derived from perception and from thought. Prior work supports the viability of the model. The present project develops two new directions: (1) Several studies of memory for simple words or pictures are proposed, using reaction time measures to test the hypothesis that perceived and imagined information show different patterns of activation during remembering. These expected differences in "revival functions" should reflect differences in trace characteristics. (2) Several studies are proposd in which memories for autobiographical events (both real and simulated) are investigated in order to extend the model to complex events and, especially, to explore the interrelations among characteristics of target traces, supporting memories and reasoning processes in making reality monitoring decisions. The long-term objective is to contribute to the development of a general memory model that takes into account information derived from both perception and thought and that can serve as a basis for understanding disruption of function, e.g., in thought disorder.